Hong Kong’s development chief says local construction waste, rather than imported sand, will be the major material for a controversial reclamation project, dismissing concerns that a shortage of sand might inflate costs.

Michael Wong Wai-lun yesterday explained to the media the cost estimates for the Lantau Tomorrow Vision project, announced this month as the government’s grand plan to tackle land shortage, after a media report suggested the high cost of marine sand could send the cost of the reclamation project out of control.

The Lantau scheme, covering reclamation of 1,700 hectares from the sea, involves the construction of artificial islands off Lantau Island in western Hong Kong. The government says the project would build Lantau into a new metropolis.

The plan has prompted thousands of people to take to the streets in protest at the high costs. Some are also dissatisfied with the way the announcement pre-empted an ongoing public consultation on ways to deal with land shortage.

The secretary for development said the Lantau project would rely more on local construction waste as fill materials, instead of imported marine sand.

“Construction waste will be a major component and form a considerable percentage of the amount of fill, but an exact figure can only be obtained after some engineering studies,” he said outside a district council meeting.

Hong Kong produces 15 million tonnes of construction waste every year, enough to reclaim 60 hectares of land, he added.

Wong spoke days after Factwire reported that a shortage of marine sand in southern China, a possible source of fill supply for Hong Kong, could mean the cost of the Lantau scheme would rocket.

The report did not give an estimate of the total cost, but said the cost of purchasing fill materials alone for the whole 1,700-hectare reclamation could be as high as HK$59.9 billion.

The cost for purchasing mainland marine sand for Tung Chung, where water is shallower and cheaper to reclaim land, was set at HK$950 per sq ft in the contract signed in January, Wong said. Accordingly, the per-square-foot cost for Lantau was adjusted to from HK$1,300 to HK$1,500.

Raymond Chan Kin-sek, retired head of the government’s geotechnical engineering office, said Wong’s estimate based on the recent Tung Chung project was “fair”, but costs for such a huge reclamation are hard to estimate accurately.

The depth of the water at the sand-sourcing area, the haulage distance from Hong Kong, and sand quality were among the variables that affect the price of marine sand, Chan said.

“You might have got a reasonable price for Tung Chung, but if you need to find another source of marine sand for Lantau, the whole calculation would work out differently,” he said.

Edward Yiu Chung-yim, a former lawmaker representing the architectural, surveying, planning and landscaping sector, said that despite Wong’s assurances, the cost of the Lantau project would only soar owing to the keen demand for construction materials from several major infrastructure projects in Hong Kong.